Hi Bill,
> The "small feature" is the ability to download DSS-2 R and
> DSS-2 B images, and combine them on-screen to get a
> "sort of" color image. I say "sort of" because there is no
> DSS-2 G, so you're only getting two-thirds of the Real Story.
> Still, even that can be helpful sometimes.
nice feature. Just tested it, and though it made Guide rather sluggish when it
came to display speed, it was a good start :) And it sort of fixed a bug in my
previous version of Guide, where it would download DSS-2 images as gifs (which
Guide would not display at all well).
Anyway, as for getting the final one-third of the Real Story, there's a way to
fake it. Mikkel Steine, the guy with the Deep Sky Browser at messier45.com
(which some of you may be familiar with), have taught me some Photoshop tricks
to create false color images from DSS-2 which at least look nice. Here's how:
1) Download red and blue images
2) align them
3) Convert the red image to RGB
4) Paste the blue image into the Blue channel of the red image
5) Apply the blue image to the green channel at 50% (this is the 'fake' part)
6) Adjust contrast etc.
Step 5 exploits the fact that green light is halfway between red and blue light
in the spectrum. It's not scientifically viable, I suppose, but it makes for
beautiful images. Here's Mikkel's collection:
http://messier45.com/cgi-bin/photo.pl?dir=Astrophoto/DSS_Colour_Images
Last summer I download 32 60'x60' DSS-2 images for a mosaic of the Belt area of
Orion. It made for a very nice poster measuring 136 cm on a side. I've put up a
"thumbnail" on my site for those interested:
http://www.astro.uio.no/~arildmi/Hente/OrionsBelte_rgb_dwnszd.jpg (282 Kb)
This image is a severely scaled down version. The original was 12,000+ pixels on
a side. This is too much even for the poster size I chose. 7,600 x 8,300 pixels
was enough. Anyone with acessibility and desire to make a great poster may
contact me offlist, if they want a copy of the Tif file.
Now, that's quite a digression. Sorry about that, but I couldn't resist it. Now,
back to the bugs :)
The asteroid list shows nicely in my Quick Info dialogue.
But, there's something odd about the zoom levels. It was like this in the
previous version, and nothing changed with the March 29 update. This is what
happens: I'm at zoom level 8 and press 7 to go to Level 7. What happens is not
that Guide zooms out, it only displays less stars (it drops the default 1.3
magnitudes between levels). Now, why doesn't Guide zoom?
Yet, here comes the weirdest thing: I'm at Level 6, press 7, Guide zooms to
Level 8, but shows stars of Level 7! Interesting :)
And I have one final wish concering downloading of DSS images, USNO data or
whatever. Guide is put together such that it downloads the stuff silently in the
background. This is great, but still I'd like to have some sort of notification
from Guide to state that "download complete" or some such. Of course, if you do
nothing but wait, you will probably see the image on the screen, but sometimes
things are rather slow, and it makes you wonder if Guide just gave up, or if
it's working.
Thanks.
Best regards,
Arild :)
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